1. Field of the Invention
This invention relates to foamed polymeric compositions which are especially useful as insulating, caulking and sealing compositions.
2. Description of the Prior Art
Insulating, caulking and sealing compositions are known. These conventional compositions include a wide range of compounds which are used in the construction, manufacturing and transportation industries. These compositions are used to seal joints or voids against water and water vapor, air and other gases, dust, sound, vermin, heat and cold, and to insulate piping and heating systems to prevent heat loss. Specialized applications require resistance to certain chemicals or atmosphere. Some compounds are applied after the structure is complete, as in masonary joints; others are applied at the time of manufacture, or in automobile and trailer bodies.
One type of caulking composition which has attained widespread popularity is the type based on polymers and mixtures of polymers. For example, U.S. Pat. No. 3,551,379 to Reinhard, et al. describes polymeric caulking compositions based on mixtures of polymers of esters, of ethylenically unsaturated carboxylic acids having three to five carbon atoms, and alkanols having one to twelve carbon atoms. In general, these caulking and sealing compositions are prepared by melting together the components or by mixing solutions of the polymers, or by mixing suitable monomers with bitumen, tar or pitch and effecting polymerization when these mixtures are used.
These conventional caulking compositions are available in a variety of forms and packages, which are dependent on the form in which the composition is to be applied and its physical properties. For example, they are supplied generally in the form of knife- or gun-grade compositions. The knife-grade materials are the stiffer of the two, and lend themselves to putty-knife application. The gun-grade compositions are extruded through an orifice, using a hand or pressure-operated caulking gun.
The use of aqueous polymer dispersions for gunnable or extruded caulking compositions has gained wide acceptance because of their ease of cleaning. The aqueous polymer dispersions are readily removed from tools, hands, etc., because of their dispersibility in water. They have the further advantage of being non-flammable and having low odor characteristics. The acrylic aqueous polymer dispersions also have excellent outdoor stability and can be painted over after approximately two hours of drying. However, these compositions as well as solvent basic formulations suffer from a number of inherent disadvantages. Normally, these compositions must be dispensed from a cartridge through the use of a caulking gun because of their high viscosity.
The cartridges in which these compositions are packaged are usually the type having an enclosed plastic nozzle through which the composition is dispensed. When used a portion of the plastic nozzle is cut off, forming a dispensing orifice which will dispense caulking composition in a certain cylindrical size which is usually called by those skilled in the art "the bead size". This is disadvantageous for the following reasons. First, the bead once dispensed must be forced into the crack which is to be sealed to afford a flush, even, unabrasive finish. The act of finishing the bead is called "tooling." The tooling is done with a variety of tools, depending on the surface characteristics of the area to be caulked. The tools will vary from putty knives, spatulas, cornering knives or even the use of fingers as a finishing tool. Some mechanics will bevel the cut on the tube orifice and use the tube as the tooling device as the caulk is dispensed. This is done by applying pressure on the existing caulk with one hand while simultaneously moving the gun in the direction of the exiting caulk and using the trigger on the gun with the other hand. This method works very effectively where the surface is perfectly smooth and provided that the mechanic is skilled in coordinating these simultaneous manipulations. However, where the surface is not smooth which is the majority of the cases such as situations where cedar shakes and other irregular sidings are being caulked, the tooling of the dispensed caulk is necessary.
A second disadvantage is associated with varying the bead size. When a portion of the plastic nozzle is cut off, it is impossible to further restrict the exiting bead for smaller cracks. Thus, excess quantities of caulk are dispensed, and must be disposed of during the tooling procedures. It is apparent this leads to a waste of caulking material.
A third disadvantage associated with known gunnable and extrudable caulking compositions is that known methods of dispensing these compositions such as the use of a caulking gun or putty knife requires the use of two hands. Thus, the use of these methods is restricting and dangerous when the methods are employed in situations where at least one hand is required for safety reasons. For example, the physical limitation of using two hands can be extremely dangerous in caulking a house where it is often necessary to work on a ladder at some distance from the ground and at least one hand is required for balancing.
Another disadvantage associated with the use of conventional gunnable or extrudable caulking compositions, is that at temperatures below 40.degree. F., they become to viscous to be gunned or otherwise extruded. This necessitates the added inconvenience of heating conventional caulking compositions when operating at temperatures lower than 40.degree. F.
Accordingly, there is a need for a polymeric caulking composition that cures the aforementioned disadvantages of the conventional knife and gun-grade compositions. More specifically, there is a need for a caulk that is self-leveling; (does not need tooling) can be dispensed with convenient adjustment of the bead width; can be dispensed using one hand thus making the caulking process safer; and finally, a caulk which can be dispensed at temperatures lower than 40.degree. F. Those of skill in the art have suggested the use of foam polymeric compositions for caulking and insulating.
One drawback of these compositions has been the difficulties associated with preparation of the foamed caulking material. Heretofore, foamed materials have been generally prepared by processes which are not suitable for use in the home or for application in the field. Recently, foamable compositions have been prepared by mixing a polymer, and a polymersoluble inert blowing and propelling agent under pressure in an aerosol container. The blowing agent is usually a generally volatile organic liquid which vaporizes when released from the container, and thereby foams the polymeric material. For example, U.S. Pat. No. 3,640,916 describes foamed caulking and insulating compositions based on a cross-linked acrylic emulsion polymer and in which various hydrocarbons and halogenated hydrocarbons are the blowing and propelling agent. These compositions have not been acceptable as caulking compositions because they are not self-leveling. As a consequence use of aforementioned invention leads to caulks which require tooling. If not tooled the physical properties of the caulk are unacceptable in that they form a very low density foam with poor physical characteristics. These caulks expand to at least six times their original volume forming a low density cylindrical bead or a collapsed cylindrical bead which on drying leads to an unsightly wrinkled effect.
Accordingly, it is an object of this invention to provide a foamable caulking composition, which obviates the defects of known caulking compositions.
It is another object of this invention to provide a foamable caulking composition which is resistant to environmental factors, and which adheres well and exhibits the so called self-leveling characteristic.
It is still another object of this invention to provide a caulking composition that can be conveniently used at temperatures of less than 45.degree. F.
It is also an object of this invention to provide an aerosol dispensed caulking composition which can be used in the home or in other like field environments and which can be dispensed in a tight ribbon.
It is yet another object of this invention to provide a foamable caulking composition which can be dispensed from an aerosol container in ribbons of varying sizes.
It is still another object of this invention to provide an aqueous polymeric based caulking composition which can be dispensed in small cracks or crevices.
It is yet another object of this invention to provide a foamable aerosol dispensed aqueous polymer based foam composition which forms a foam caulking composition which is self leveling, and which does not drip from overhead or vertical surfaces.
It is still another object of this invention to provide an aerosol container including the caulking composition of this invention, said container being adapted to dispense the composition in ribbons of varying size.
Other objects and advantages will be apparent to one of skill in the art from the following description and appended claims.